Motor-driven Handpiece

ABSTRACT

A motor-driven handpiece, which has a grip sleeve with a head area for mounting a tool, in particular for the preparation of tooth substance and/or bone substance, in which the head area is at least partially surrounded or encapsulated by a thermoplastic material which, compared to the material of the rest of the grip sleeve, has a lower thermal conduction value.

The present invention relates to a motor-driven handpiece according to the pre-characterizing clause of claim 1, which has a grip sleeve with a head region for mounting a tool, in particular for the preparation of tooth substance and/or bone substance.

In dental medicine, therapeutic measures are primarily carried out, now as before, with the aid of dental handpieces which comprise and drive a tool for machining teeth in a material-detaching manner. In this connection, use is customarily made of so-called “drilling handpieces” which comprise, at their front end region, a rotatably mounted tool in the form of a drill, with the aid of which the tooth substance is machined in a material-ablating manner. Whereas turbine drives have predominantly been used in the past, increased use has recently been made of dental handpieces in which an electric motor that drives the drill is provided as the driving unit.

While the treatment is being carried out, the head region of the dental handpiece is usually located, with the drill, inside the patient's oral cavity, or at least in the vicinity thereof. This area of the patient is relatively sensitive to pain, and care should therefore be taken to avoid harm to the patient as far as possible.

Now the present invention is concerned with the problem that, for example, prolonged use of the drive, but particularly any malfunctions in the drive or its drive train, might lead to overheating of the handpiece, which could ultimately cause burns to the patient. The underlying object of the present invention is to reduce the risk of such burns for the patient.

This object is achieved by means of a motor-driven handpiece having the features in claim 1, and also by means of a cap, in accordance with claim 8, for use in a corresponding motor-driven handpiece. Advantageous further developments of the invention form the subject of the dependent claims.

The solution according to the invention is based on the idea of surrounding or sheathing the head region of the handpiece, at least partially, with a material with the aid of which thermal insulation is achieved.

According to the present invention, therefore, a motor-driven handpiece is proposed which has a grip sleeve with a head region for mounting a tool, in particular for the preparation of tooth substance and/or bone substance, wherein, according to the invention, the head region is at least partially surrounded or sheathed with a thermoplastic material which, compared to the material of the rest of the grip sleeve of the handpiece, has a lower thermal conduction value. In this connection, the thermal conduction value of the thermoplastic material is, in particular, lower than that of metals.

The head region may be completely surrounded or sheathed with the thermoplastic material, in which case it might conceivably be possible, for example, to injection-mould the thermoplastic material around the head region. As an alternative to this, however, it might also be conceivably possible to fit the thermoplastic material to the head region in the form of a detachable cap. This cap can then be slipped over the head region in a simple manner, but can also be removed from the handpiece again for cleaning and/or sterilization purposes.

The thermoplastic material may be provided, in part, with elevations or projections so that, ultimately, burns can be avoided to a very great extent because of the reduced area of contact with the patient.

According to one advantageous further development of the invention, provision may also be made for the outward appearance of the thermoplastic material to be temperature-dependent. In particular, a material might be chosen whose color changes with the temperature, so that not only is the transfer of heat prevented but at the same time an indication is also given if, for example because of a malfunction in the handpiece, the temperature is rising to an undesirably great extent. This therefore makes it possible once again to improve the operating safety of the handpiece.

Also proposed according to the invention is a cap for use with a motor-driven handpiece which has a grip sleeve with a head region for mounting a tool, in particular for the preparation of tooth substance and/or bone substance, wherein the cap is designed to be detachably fastened to the head region and is formed from a thermoplastic material which has a lower thermal conduction value than metal.

The invention will be explained in greater detail below with the aid of the accompanying drawings, in which:

FIGS. 1 and 2 show views of a motor-driven handpiece configured in accordance with the invention;

FIGS. 3 and 4 show views of the front end region of the handpiece according to the invention; and

FIGS. 5 to 8 show views of a variant of a cap according to the invention for use in a dental handpiece.

FIGS. 1 and 2 show a dental drilling handpiece which is provided, as a whole, with the reference numeral 1 and has an elongated grip sleeve 2 which is slightly angled in the central region. Constructed at the rearward end of the grip sleeve 2 is a coupling region 3 via which the handpiece 1 can be connected to a supply hose—of which no further details are represented—belonging to a dental treatment station. The handpiece 1 is fed via this supply hose with, on the one hand, electrical energy and also, on the other hand, treatment media such as air and/or water which are used, for example, for cleaning and/or cooling the site to be machined. In this connection, the coupling region 3 is preferably configured in such a way that the handpiece 1 is freely rotatable in relation to the supply hose.

A head region 5, which comprises, in particular, means for receiving and mounting a dental drill, is constructed at the front end of the grip sleeve 2. In particular, a plug-in aperture 6 (see FIG. 3), into which the shaft of the drill can be introduced, is constructed at the lower end of the head region. By means of a special clamping mechanism inside the head region 5, the drill is then held in a reliable and rotatable manner in such a way that it is oriented substantially perpendicularly to the longitudinal axis of the grip sleeve 2. A push-button 7 for releasing the clamping mechanism is arranged at the opposite end of the plug-in aperture 6.

The grip sleeve 2 also serves to receive a driving unit which may, in particular, be an electric motor. Electric motors of this kind have been employed to an increasing extent recently, since they open up improved possibilities as regards control, compared to the turbine drives which have been predominantly used hitherto. Thus it is possible, in particular, to set the rotational speed and torque of the drill in a better and more precise manner. The electric motor is then coupled to the drill receptacle in the head region 5 via suitable couplings and drive shafts, so that the rotation of the motor shaft can be transmitted to the drill.

Now if the motor is operated in a sustained manner, or there is a malfunction in the motor or in the means for transmitting the rotation to the drill, there is a danger that the handpiece 1, in particular its head region 5, will warm up. In this case, excessive warming-up can lead to painful burns in the patient's oral region, which are to be avoided. For this purpose, a special cap 10, which will be described in greater detail below, is provided in a manner corresponding to the exemplified embodiment in FIGS. 1 to 4.

The cap 10 constitutes a protective cap, with the aid of which thermal insulation is to be achieved in the event of excessive heating-up of the handpiece 1 or of the head region 5. For this purpose, the cap 10 consists of a thermoplastic material which has a low thermal conduction value compared to the material of the rest of the grip sleeve 2. The thermal conduction value of the material of the cap 10 should lie, in particular, below the conduction value of metal, in particular of steel. In this connection, the cap 10 is shaped in such a way that it can be slipped, in a simple manner, onto the front end region of the grip sleeve 2 with the head region 5. For this purpose, it has a front annular region 11 which, in the attached state, almost completely encloses the head region 5 of the handpiece 1. Extending sideways from this annular region 11 is a supporting region 12 which, in a manner corresponding to the representations in FIGS. 1 to 4, surrounds the upper half of the front end of the grip sleeve 2. The material of the cap is thermoplastic and accordingly has a certain flexibility. Now the dimensions of the cap 10 are such that the cap 10 can be snapped onto the front end region of the grip sleeve 2 of the handpiece 1 and is seated securely and reliably at that point. At the same time, however, the possibility also exists, with this solution, of removing the cap 10 again in order, for example, to clean the handpiece 1 or to clean or sterilize the cap 10. For this purpose, the material of the cap 10 is preferably such that repeated cleaning or sterilizing operations are possible. As an alternative to this, however, it would also be conceivably possible to bond the cap 10 to the handpiece 1.

The use of the protective cap 10 with the low thermal conduction value (preferably<5 W/mK) leads, then, to the fact that no heat is transmitted to the outside by the cap 10, even if the head region 5 of the handpiece is heated up to a fairly great extent. As a result of this, the risk, or at least the severity, of burns in the patient's oral cavity in the event of malfunctions in the handpiece can be markedly reduced.

FIGS. 5 to 8 show an alternative form of embodiment of a cap 10, which is basically the same, in its make-up, as the cap in FIGS. 1 to 4. The special feature now lies in the fact that the outer face, in particular of the annular region 11, is provided with a structure 13 which has elevations or projections arranged in a regular pattern. As a result of this measure, the contact area when touching, in particular, soft parts within the patient's oral cavity is further reduced, resulting in additional safety.

As an alternative to the exemplified embodiments represented, in which detachable caps are attached to the front end region of the handpiece, it would also be conceivably possible to provide the handpiece with a suitable coating, for example a coat of lacquer or the like. In this respect, suitable lacquers or materials, in particular Rilsan®, are known, which could be used in order to coat, or injection-mould around, the head region completely, or at least partially. The unlocking button 7 could also be coated in the process.

Provision could also be made for the material of the cap, or the thermal insulating material applied directly to the handpiece, to be configured in such a way that its outward appearance is dependent upon the temperature. In particular, use could be made of a material which changes color when a rise in temperature occurs, as a result of which a user of the handpiece would be able to detect, relatively quickly, the occurrence of a malfunction which is leading to an unwanted rise in temperature. The operating safety could therefore be additionally increased as a result of this measure.

All in all, therefore, it is possible, by means of the measures according to the invention, to avoid, or at least greatly mitigate, burns in a patient's oral region. 

1. Motor-driven handpiece comprising a grip sleeve with a head region for mounting a tool, wherein the head region is at least partially surrounded or sheathed with a thermoplastic material which, compared to the material of the rest of the grip sleeve, has a lower thermal conduction value.
 2. Motor-driven handpiece according to claim 1, wherein the head region is completely surrounded or sheathed with the thermoplastic material.
 3. Motor-driven handpiece according to claim 1, wherein the thermoplastic material is injection-molded around the head region.
 4. Motor-driven handpiece according to claim 1, wherein the thermoplastic material is fastened to the head region in the form of a detachable cap.
 5. Motor-driven handpiece according to claim 1, wherein the thermoplastic material is at least partially provided with elevations or projections.
 6. Motor-driven handpiece according to claim 1, wherein the outward appearance of the thermoplastic material is temperature-dependent.
 7. Motor-driven handpiece according to claim 1, wherein the thermoplastic material has a lower thermal conduction value than metal.
 8. Cap for use with a motor-driven handpiece, the handpiece comprising a grip sleeve with a head region for mounting a tool, wherein the cap is adapted to be detachably fastened to the head region and is formed from a thermoplastic material which has a lower thermal conduction value than metal.
 9. Cap according to claim 8, wherein a surface of the cap is provided, at least in part, with elevations or projections.
 10. Cap according to claim 8, wherein the outward appearance of the thermoplastic material is temperature-dependent.
 11. Motor-driven handpiece according to claim 1, wherein the tool is a tool for the preparation of at least one of a tooth substance and a bone substance.
 12. Motor-driven handpiece according to claim 6, wherein the color of the thermoplastic material is temperature-dependent.
 13. Cap according to claim 8, wherein the tool is a tool for the preparation of at least one of a tooth substance and a bone substance.
 14. Cap according to claim 10, wherein the color of the thermoplastic material is temperature-dependent. 